International Journal of Science and Research (IJSR)
ISSN (Online): 2319-7064
Impact Factor (2012): 3.358
Review Modeling of Reactive Distillation Column
for the Production of Ethyl Acetate through
Esterification
Shivali Arora1, Prashant Srivastava2
1
School of Chemical Engineering, ITM University, Gwalior, India
School of Chemical Engineering, ITM University, Gwalior, India
2
Abstract: Reactive distillation is the combination of reaction and separation in a same column. It is an attractive option whenever
liquid phase reactant is in large excess. The energy requirement of the conventional column is very high and requires large recycling
costs. RD column works close to the stoichiometric feed conditions thereby eliminating recycling costs and increases the efficiency of
the column. Reactive distillation is attractive when the liquid phase reactant is in large excess. The conversion of homogeneous and
heterogeneous reaction takes place in reactive distillation column in which the reaction takes place in the presence of catalyst.
Designing, operation and process development of RD column is highly complex task. Ethyl acetate and water is produced by the
esterification of acetic acid and alcohol using catalyst such as sulphuric acid or ion exchange resins. The system temperature is kept at
70⁰C and pressure of 1 atm. The reaction is endothermic, second order and reversible. Acetic acid and ethanol reacts according to the
reaction to produce ethyl Acetate and Water. The reaction is highly equilibrium limited. The products are continuously sent to
separation thus driving the equilibrium towards right direction. The process is non-ideal due to the presence of ethanol, acetic acid,
ethyl acetate and water. There is the formation of five normal azeotropes i.e. ethanol-water, Water-acetic acid, ethyl acetate –ethanol,
ethyl acetate-water, ethanol-acetic acid-ethyl acetate. Separation of these azeotropes is very difficult. In the proposed work review on
modeling of the reactive distillation column for the production of ethyl acetate is given.
Keywords: Reactive Distillation, Ethyl Acetate, Modeling, Endothermic, Mass-Balance.
1. Introduction
Ethyl Acetate is an important solvent widely used in many
industries for the production of varnishes, ink, synthetic
resins and adhesive agents it can be produced directly from
ethanol (EtOH) and acetic acid (HAc) under acidic
conditions. The reaction condition for the production of ethyl
acetate is endothermic and there must be the low conversion
of the reactants. This condition is very difficult to maintain
and requires high capital investment and high energy costs.
Thus Reactive distillation provides a good opportunity for
the production of ethyl acetate. The key advantage for this is
improved selectivity, increased conversion, heat integration
benefits, lowers the economy by reducing the number of
columns for separation operation and there is an avoidance of
azeotropes in the reaction.
The Reactive distillation is the combination of reaction and
separation in a single unit. The performance of the reactor is
more than conventional and the sequential approach. In
reactive distillation the performance of the reactor is
increased due to the interest of researchers and scientists in
this field. It is used more frequently in industries as much of
the experimentation and research take place in this area.
There is no model and design available in literature that
proves the usability of the process with its advantages. Most
of the design process includes limitations and its simplified
assumptions. None of the process deals with realistic model.
Paper ID: SUB141160
In-spite of number of models available in the literature, the
entire model of a process depends on the intelligence of a
researcher. The choice of correct feed location, reflux etc.
The study of RD can be done in ways as: feasibility,
simulation results, modeling and design, experimental
process and pilot plant.
The modeling of RD column is very difficult task due to
reaction and separation in the same column. The process of
RD was first patented in 1920s and was commercialized on
1980s since Eastman Company owned and run a commercial
process for the production of methyl acetate. Esterification,
trans-esterification and hydrolysis reaction were firstly being
studied in this process with homogeneous self-catalyzed
reactions. Heterogeneous reaction in RD column was first
studied in 1966 by spes in which the reaction takes place in
the presence of a catalyst. The development of RD model
was reviewed by taylor and Krishna in 2000.
2. Previous Work
Moses O.Tade et.al. (2003) provided a case study on ETBE
by modeling a column and their significance on process
development was discussed in “Modeling and control of
reactive distillation systems”. They had developed and
simulate RD column for the production of methyl acetate. An
optimum value of reflux ratio is obtained with minimum
number of stages. The equilibrium design of the process is
verified with a kinetic simulation near operating conditions.
The feasibility results are compared with the findings of
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International Journal of Science and Research (IJSR)
ISSN (Online): 2319-7064
Impact Factor (2012): 3.358
bessling et. al. experimental results and were found very
close to it.
national standards (ASTM D 6751) for its viscosity and total
glycerol.
JianjunPeng et. al. (2003) developed dynamic rate based and
equilibrium based model of packed reactive distillation
column for the production of tert-amyl methyl ether(TAME).
Two models were developed, implemented in gPROMS,
dynamic simulation was carried out and dynamic behavior of
reactive distillation column for the production of TAME was
studied. There was similarity in two models except some
steady-state values.
Two models were developed for equilibrium based model
and rate based model. Both the models are found to be same
in there approximate values.
Muhamad Nazri Murat et. al. (2003) developed an
equilibrium stage-wise reactive distillation model and
process simulation was done. The algorithm for solving
mathematical model was given by the set of differentialalgebraic equations based on relaxation method. Simulation
was performed on PC Pentium processor using a
programming language in Fortran90. The results were
validated from simulation result from the data in literature.
The model so developed can give results on high isobutene
conversion for the heterogeneous system as required for the
industrial applications for the production of MTBE. The
results were given in form of comparison on temperature
profile, liquid composition profile and operating conditions
of reactive distillation column. There work had shown
promising results and the model to be used as a tool for the
designing of reactive distillation column.
They had developed a model based on steady state simulation
consists of number of ordinary differential equations and
algebraic equations. Relaxation method is used for the
solution of these equations. This method provides the better
convergence of the equation and gives the solution to the
equations. The model had provided the results as good as that
of aspen plus simulation results.
Figure 1: Production of Biodiesel in RD column
Myrian Schenk (2004) et. al. had studied a mixed-Integer
Dynamic Optimization (MIDO) model In their study they
developed a model and studied an integration between
process operability and process modeling for the production
of ethyl acetate. They had presented a feasibility of the model
under certain bounded conditions for 17% to 20% savings
over the design originally present in literature.
They had considered an advanced MIDO framework for
process design, process control and the operability of the
column. The result obtained is having a simultaneous
approach rather than a sequential approach. The model
developed by them is having a control system based on PI
controller.
I-Kuan Lai et.al. (2008)Studied the production of ethyl
Acetate in reactive distillation column and realizes the type-II
reactive distillation column and also study the initial feed
conditions to the column and a startup procedure for the
continuous production of the product. The results are given
for six experimental runs show that, by controlling the initial
charges of the column, proper inventory hold ups and proper
inventory conditions will increases the purity of ethyl acetate.
Joe C. Thompson. et. al. (2004) prepared lab scale sieve tray
RD column for the production of biodiesel in reactive
distillation column. The experiment was developed for the
trans-esterification reaction in the presence of a catalyst
between vegetable oils and alcohol. The reaction was carried
out in 100% excess of that required for the reaction to
achieve maximum conversion to drive reversible process in
forward direction in batch or continuous reactors.
The paper shows an experimental study for the production of
ethyl acetate of RD II process consists of a reactive
distillation column, a stripper and the recycle. Six
experimental runs with different initial feed conditions are
run and showed that the performance of the reactor depends
on the initial conditions.
The reactive distillation so developed has been found feasible
for the production of biodiesel. The main objective of the
study is reducing the alcohol to oil ratio. The study of the
paper shows that the optimum temperature for the production
of biodiesel is 66⁰C with the molar ratio of 4:1 and a prereactor. The biodiesel obtained in this experiment meets the
Kwantip Konakom et. al(2010) had worked upon the purity
of ethyl acetate to produce the product of approximately 90%
pure. In the previous works ethyl acetate of 52% purity was
achieved due to equilibrium limitations. The purity of the
product is increased by installing many sequential units
which requires large investments of the income.
Paper ID: SUB141160
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International Journal of Science and Research (IJSR)
ISSN (Online): 2319-7064
Impact Factor (2012): 3.358
Figure 3: Biodiesel production process by RD
Ahmed D. Wiheeb et.al. (2011) they had provided RD
column for the production of ethyl acetate and simulated it
with the simulation tool HYSYS.
Figure 2: Model of RD column
So a batch column with reaction and separation in a single
unit was proposed with the purity of 90% by mole. This
purity cannot be achieved by constant reflux. Based on the
open loop simulation the optimization problem is formulated
for the product specification, re-boiler heat duty and batch
operating time. The optimum reflux rate is achieved by
optimizing the reflux starting with the minimum. The
simulation of the process is done to obtain the purity of 90%
by optimization programs.
Chokchai Mueanmas et. al. (2010) had developed a RD
column for the production of Biodiesel. Earlier in
conventional process alcohol was feed to the reactor in
almost 100% excess which leads to large economic costs.
Thus RD is used which drives the reaction towards the
equilibrium and decreases the consumption of alcohol. They
had studied on various parameters of the column to increase
the rate of conversion and decrease the amount of alcohol.
They had concluded that the molar flow rate of 900ml/hr. reboiler temperature of 90⁰C, molar-ratio of 4:1 of methanol
and alcohol with a residence time of 5 min. can give 92.70%
biodiesel purity.
Paper ID: SUB141160
The reaction and separation takes place in the same column
in a single column. The thermodynamic properties are
calculated by Wilson, NTRL and UNIQUAC models which
are available in HYSYS simulator programs. Effect of
temperature at bottom product, reflux ratio and composition
of water in the feed, effects of three feed conditions are
studied (upper, split and middle). The results had shown that
the best conditions are that the bottom conditions are at
83⁰C-86⁰C, reflux ratio at (2-5) with no water content in the
feed and at split conditions. It was a successful simulation in
HYSYS. The findings in the paper are that the most of the
variables on the top of the column is not important. The
water content in the feed is reduced leading to less efficiency
of the tower and hence the production of EtAc is reduced.
The simulation of the process is done and the best operating
conditions are found to be: The bottom temperature of the
column is 85-87⁰C. The best feed conditions are found as the
split feed conditions. The molar reflux is in range of 2-5.
Wilson model was accepted as the best model for the
calculation of all thermodynamic properties.
Nghi Nguyen and co-workers in 2011 had worked upon the
production of ethyl dodeconoate using lauric acid and
methanol with a solid catalyst of sulfated zirconia is studied.
They had studied this system in two ways: In the first system
methanol recovery column followed the distillation column
and in other the thermally coupled methanol recovery and
reactive distillation column was designed. The thermal
recovery column consumes less energy. This is done by inter
connection liquid and vapor streams thus eliminating the reboiler and condenser. The distillation sequences is optimized
and found that there is 13.1% of less energy requirement as
in reactive distillation column and the recovery of the
methanol was increased by 50%. The energy loses in the
column is reduced by 281.35 kW which is 21.7% of the
available energy required. In addition to it the composition of
the column was also improved. There is less water required
as that of original water content which decreases the
deviation of the catalyst during the reaction.
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This work improves the energy requirement in the column.
Thus the capital investment and the operating cost have
reduced as that of the conventional reactive distillation
sequence. This has also decreases the energy required in
liquid-liquid extraction for the separation of the methanol and
protects the catalyst from deviation.
Luisa F. Rios et. al. (2012) had developed a model in aspen
plus 7.2 for the production of biodiesel from soya-bean oil
and ethanol in the presence of the catalyst. The experimental
studies say that the best biodiesel composition was found at
1.34% of catalyst and ethanol with a molar ratio of 8:1. The
experiment was found to be in good review because all the
process variables are carefully evaluated. The simulation of
the process is done to evaluate other variable and
optimization of the process is done. This study had showed
that using pre-reactor before the column increases the
efficiency of the column. The software for the simulation had
provided same as experimental results with slight variations.
Abdulwahab Giwa (2012) had developed a dynamic model
for the production of Ethyl acetate. The modeling for the
production of ethyl acetate was been compared with the
experimental work. The major parameters considered in the
work are top and bottom temperatures. The model considered
in the experiment was a column in which reaction takes place
in the presence of amberlyst catalyst-15 while the
rectification and stripping sections are both filled with
rashing rings. The dynamic model was developed with first
principle was solved in MATLAB R2011a.
The results of the experiment are compared with that of the
simulation results and were found in good agreement with
very small residual errors.
Raul Delgado et.al.(2012) have worked upon the control and
design of the thermally coupled distillation sequences using a
single shell divided by a wall named divided wall distillation
column. In this work the production of ethyl acetate in a
divided wall distillation column was done for the first time.
The simulation of the process was done in aspenONE aspen
plus. The results obtained in the process are in good
agreements of that of the simulation results.
The work, startup and the operation of the column to carry
out esterification reaction was successfully done. The results
obtained are compared with the simulation results and
corroborated by gas chromatography.
Priyanka Gautam et. al. (2013) had done modeling and
simulation of RD column for the production of ethyl acetate
in Aspen Plus. The effect of feed temperature and
composition was studied by varying the feed flow rates.
3. Conclusion
The modeling of RD column for the production of ethyl
acetate through esterification was reviewed in this paper. The
study had showed that the model developed are based on
various assumptions thus shows deviations from the
experimental data. The thermodynamics of liquid phase
Paper ID: SUB141160
activity coefficient controls the modeling of the process.
However user based models provides the best results.
References
[1] R. Taylor and R. Krishna, “Review: Modeling reactive
distillation,” Chem. Eng. Science, 55, 5183-5229, 2000.
[2] Al-Arfaj M. A. and Luyben, W. L. "Comparative control
study of ideal and methyl acetate reactive distillation,"
Chem. Eng. Sci., vol. 24, pp. 5039-50, 2002.
[3] Suzuki,I., Yagi, H., Kumatsu and Hirata, M.,
"Calculation
of
Multi-component
Distillation
accompanied by a chemical reaction” J. Chem. Eng. Jap
4, 26-33 (1971).
[4] Robert S. Huss, Fengrong Chen, Michael F. Malone,
Michael F. Doherty “Reactive distillation for methyl
acetate
production
Computers
and
Chemical
Engineering” 27 (2003) 1855_/1866.
[5] Jianjun Peng, Thomas F. Edgar, R. Bruce Eldridge
“Dynamic rate-based and equilibrium models for a
packed reactive distillation column Chemical
Engineering” 58 (2003) 2671 – 2680.
[6] G. Jan Harmsen “Reactive distillation: The front-runner
of industrial process intensification full review of
commercial applications, research, scale-up, design and
operation” A Engineering and Processing 46 (2007)
774–780.
[7] Nghi Nguyen “Using Thermally Coupled Reactive
Distillation Columns in Biodiesel Production Energy”
The International Journal (2011) 36: 4,838-4,847.
[8] Chokchai Mueanmas, Kulchanat Prasertsit and Chakrit
Tongurai “Feasibility Study of Reactive Distillation
Column for Trans-esterification of Palm Oils”
International Journal of Chemical Engineering and
Applications, Vol. 1, No. 1, June 2010 ISSN: 20100221.
[9] Luisa F. Rios, Edgar L. Martinez, Nivea de L. Da Silva,
Tarcisio S.S.Dantas, Rubens Maciel, Maria R. Wolf
Maciel “Biodiesel Production by an Integrated Reactive
Separation System: A Comparative Study” vol. 26,
2012.
[10] Zoltan K Nagy, Reinhardt Klein, Anton A Kiss, Rolf
Findeisen “Advanced Control of a Reactive Distillation
Column” 17th European Symposium on Computer
Aided Process Engineering.
[11] Amenaghawon, Nosakhare Andrew, Ogbeide, Samuel.E
“Modeling simulation and control of ethyl acetate
reactive distillation column using chem.-cad” Volume
Journal of Engineering and Applied Sciences 4, March
2012.
[12] Moses O. Tadé, Budi H. Bisowarno, and Yu-Chu Tian
“Modeling and control of reactive distillation systems”.
[13] Kwantip Konakom, Aritsara Saengchan, Paisan
Kittisupakorn, and Iqbal M. Mujtaba “High Purity Ethyl
Acetate Production with a Batch Reactive Distillation
Column using Dynamic Optimization Strategy”
Proceedings of the World Congress on Engineering and
Computer Science 2010 Vol II WCECS 2010, October
20-22, 2010.
[14] I-Kuan Lai , Yan-Chun Liu , Cheng-Ching Yu Ming-Jer
Lee, Hsiao-Ping Huang “Production of high-purity ethyl
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acetate using reactive distillation: Experimental and
start-up procedure” Chemical Engineering and
Processing 47 (2008) 1831–1843.
[15] Ahmed d. Wiheeb thaer a. Abdulla omar s. Lateef
“process simulation study of ethyl acetate reactive
distillation column by hysys® 3.2 simulator” diyala
journal of engineering sciences” vol. 04, no. 02, pp. 3956, december 2011.
[16] V. Pavan kumar malladi1 and nitin kaistha “reactive
distillation: control structure and Process design for
robustness”.
[17] Priyanka Gautam, Piyush Pratap Singh, Animesh
Mishra, Abhishek Singh, Shakti Nath Das, S. Suresh
“Simulation Of Reactive Distillation Column”
International Journal of Chem Tech Research coden(
usa): ijcrgg issn : 0974-4290 vol.5, no.2, pp 1024-1029,
april-june 2013.
Author Profile
Shivali Arora received the Bachelor of Technology degree
in Chemical Engineering from Anand Engineering College,
Agra. 2010 During 2010-2012, she stayed in Jaipur National
University Jaipur and worked as lecturer. She now studying
in ITM University Gwalior and perusing her Masters in
Chemical engineering Degree.
Paper ID: SUB141160
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